[maybe OT] dual or quad core mac mini for kinect tracking

I want to buy a mac mini fot kinect tracking. At the moment Apple offers an 2.0 Quadcore i7 with an intel HD 3000 384 MB shared VRAM or an 2,7 dual core i7 with AMD Radeon HD 6630M with 256 MB GDDR5 RAM
They are similar in price. Can anyone tell me if it´s better to have a faster processor or more kernals and which video card is better for Jitter processing.
below is the link to the shop in germany